1. Technical Field
The present disclosure relates to a method of using autonomic nerve fluctuations and a system that uses these fluctuations.
2. Description of the Related Art
Biofeedback technology is under study in recent years. Biofeedback refers to technology or a phenomenon that enables the state in the body of a person to be consciously adjusted by feeding back information of which the person is not aware in an engineering way so that the person becomes aware of the information. For example, a stimulus that generates a physiological state homogeneous to a target physiological state of a test subject is applied to the test subject in consideration of the current heart rate, pulse rate, breathing rate, and other bio-information of the test subject. Therefore, the current physiological state of the test subject can be alleviated, and the test subject can be gradually induced to the target physiological state.
Conventional known biofeedback apparatuses are described in, for example, Japanese Unexamined Patent Application Publication Nos. 2008-125802 and 2001-252265.
Japanese Unexamined Patent Application Publication No. 2008-125802 discloses a technology by which biofeedback is performed by using a heart rate, myoelectricity, a blood pressure, a breathing rate, galvanic skin reflex, and the like. FIG. 11 illustrates a conventional biofeedback apparatus 600 described in Japanese Unexamined Patent Application Publication No. 2008-125802. A physiological measurer 63 in the biofeedback apparatus 600 obtains physiological information from a test subject (sometimes referred to as the user). The obtained information is sent to a state inferrer 64, which calculates an autonomic nerve activity index, after which the obtained information is transferred to a state determiner 65 and a control determiner 66 in that order. Finally, a stimulus presenter 68 presents some kind of stimulus to the user. In an embodiment in Japanese Unexamined Patent Application Publication No. 2008-125802, known heart rate variability biofeedback is used (see M. Sakakibara, P. Lehrer, “Heart rate variability biofeedback”, Japanese Journal of Biofeedback Research, Vol. 40, Issue 2, 43-46 (2013), for example).
Japanese Unexamined Patent Application Publication No. 2001-252265 discloses a technology by which biofeedback is performed by using brain waves (or magnetoencephalography), biochemical reactions, a wink frequency, a skin resistance, sweating, voice intonation, body motion, mouse motion, dryness, head motion, a pupil size, facial expressions, a heart rate, a pulse rate, a breathing rate, a breathing state, and a body surface temperature. In Japanese Unexamined Patent Application Publication No. 2001-252265, the metal activity of the user is inferred by using the above information, and stimuli with intensities that are changed with time are applied to the five senses of the user by using a 1/f fluctuation theory or the like. FIG. 12 illustrates a conventional biofeedback apparatus described in Japanese Unexamined Patent Application Publication No. 2001-252265. A mental activity detector 71 detects various biological reactions of the user. A mental activity determiner 76 comprehensively analyzes the detection results. As a result, the mental activity state of the user is determined. A stimulus generator 73 applies stimuli having a time-varying intensity to the five senses of the user so as to attain the mental activity selected by a mental activity selector 74 as a target.